185 lines
4.9 KiB
C
185 lines
4.9 KiB
C
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/***************************************************************
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crc's _ _
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(_) | ___
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| | |/ _ \ a tiny virtual computer
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| | | (_) | 64kw RAM, 32-bit, Dual Stack, MISC
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|_|_|\___/ ilo.c (c) charles childers
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**************************************************************/
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#include <stdio.h>
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#include <fcntl.h>
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#include <unistd.h>
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#define T ds[sp] /* Top of Data Stack */
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#define N ds[sp-1] /* Next on Data Stack */
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#define R as[rp] /* Top of Address Stack */
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#define V void
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#define I int
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#define C char
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I ip, /* instruction pointer */
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sp, /* data stack pointer */
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rp, /* address stack pointer */
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ds[33], /* data stack */
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as[257], /* address stack */
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m[65536]; /* memory */
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C *blocks, /* name of block file (ilo.blocks) */
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*rom; /* name of image (ilo.rom) */
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/* the other variables are used by the various
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functions for misc. purposes */
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I a, b, f, s, d, l;
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C i[1];
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V push(I v) { ds[sp + 1] = v; sp += 1; }
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I pop() { sp -= 1; return ds[sp + 1]; }
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V load_image() {
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f = open(rom, O_RDONLY, 0666);
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if (!f) { return; };
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read(f, &m, 65536 * 4);
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close(f);
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ip = sp = rp = 0;
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}
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V save_image() {
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f = open(rom, O_WRONLY, 0666);
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write(f, &m, 65536 * 4);
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close(f);
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}
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V block_common() {
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b = pop(); /* block buffer */
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a = pop(); /* block number */
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lseek(f, 4096 * a, SEEK_SET);
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}
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V read_block() {
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f = open(blocks, O_RDONLY, 0666);
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block_common();
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read(f, m + b, 4096);
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close(f);
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}
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V write_block() {
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f = open(blocks, O_WRONLY, 0666);
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block_common();
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write(f, m + b, 4096);
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close(f);
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}
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V save_ip() { rp += 1; R = ip; }
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V symmetric() { if (b >= 0 && N < 0) { T += 1; N -= b; } }
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V li() { ip += 1; push(m[ip]); }
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V du() { push(T); }
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V dr() { ds[sp] = 0; sp -= 1; }
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V sw() { a = T; T = N; N = a; }
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V pu() { rp += 1; R = pop(); }
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V po() { push(R); rp -= 1; }
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V ju() { ip = pop() - 1; }
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V ca() { save_ip(); ip = pop() - 1; }
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V cc() { a = pop(); if (pop()) { save_ip(); ip = a - 1; } }
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V cj() { a = pop(); if (pop()) { ip = a - 1; } }
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V re() { ip = R; rp -= 1; }
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V eq() { N = (N == T) ? -1 : 0; sp -= 1; }
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V ne() { N = (N != T) ? -1 : 0; sp -= 1; }
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V lt() { N = (N < T) ? -1 : 0; sp -= 1; }
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V gt() { N = (N > T) ? -1 : 0; sp -= 1; }
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V fe() { T = m[T]; }
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V st() { m[T] = N; sp -= 2; }
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V ad() { N += T; sp -= 1; }
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V su() { N -= T; sp -= 1; }
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V mu() { N *= T; sp -= 1; }
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V di() { a = T; b = N; T = b / a; N = b % a; symmetric(); }
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V an() { N = T & N; sp -= 1; }
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V or() { N = T | N; sp -= 1; }
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V xo() { N = T ^ N; sp -= 1; }
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V sl() { N = N << T; sp -= 1; }
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V sr() { N = N >> T; sp -= 1; }
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V cp() { l = pop(); d = pop(); s = T; T = -1;
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while (l) { if (m[d] != m[s]) { T = 0; }
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l -= 1; s += 1; d += 1; } }
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V cy() { l = pop(); d = pop(); s = pop();
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while (l) { m[d] = m[s]; l -= 1; s += 1; d += 1; } }
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V ioa() { i[0] = (char)pop(); write(1, &i, 1); }
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V iob() { read(0, &i, 1); push(i[0]); }
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V ioc() { read_block(); }
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V iod() { write_block(); }
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V ioe() { save_image(); }
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V iof() { load_image(); ip = -1; }
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V iog() { ip = 65536; }
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V ioh() { push(sp); push(rp); }
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V io() {
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switch (pop()) {
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case 0: ioa(); break; case 1: iob(); break;
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case 2: ioc(); break; case 3: iod(); break;
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case 4: ioe(); break; case 5: iof(); break;
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case 6: iog(); break; case 7: ioh(); break;
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default: break;
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}
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}
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/* Using a switch here instead of a jump table to avoid */
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/* some issues w/relocation stuff when building w/o libc */
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V process(I o) {
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switch (o) {
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case 0: break; case 1: li(); break;
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case 2: du(); break; case 3: dr(); break;
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case 4: sw(); break; case 5: pu(); break;
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case 6: po(); break; case 7: ju(); break;
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case 8: ca(); break; case 9: cc(); break;
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case 10: cj(); break; case 11: re(); break;
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case 12: eq(); break; case 13: ne(); break;
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case 14: lt(); break; case 15: gt(); break;
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case 16: fe(); break; case 17: st(); break;
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case 18: ad(); break; case 19: su(); break;
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case 20: mu(); break; case 21: di(); break;
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case 22: an(); break; case 23: or(); break;
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case 24: xo(); break; case 25: sl(); break;
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case 26: sr(); break; case 27: cp(); break;
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case 28: cy(); break; case 29: io(); break;
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default: break;
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}
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}
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V process_bundle(I opcode) {
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process(opcode & 0xFF);
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process((opcode >> 8) & 0xFF);
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process((opcode >> 16) & 0xFF);
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process((opcode >> 24) & 0xFF);
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}
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V execute() {
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while (ip < 65536) {
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process_bundle(m[ip]);
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ip += 1;
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}
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}
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#ifndef NOSTDLIB
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I main(I argc, C **argv) {
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blocks = (argc > 1) ? argv[1] : "ilo.blocks";
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rom = (argc > 2) ? argv[2] : "ilo.rom";
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load_image();
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execute();
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for (; sp > 0; sp -= 1) printf(" %d", ds[sp]); printf("\n");
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return 0;
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}
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#else
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I main(I argc, C **argv) {
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blocks = "ilo.blocks";
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rom = "ilo.rom";
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load_image();
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execute();
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return 0;
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}
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#endif
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